1. Field of the Invention
The invention is directed to an optical fibre connector for splicing two optical fibres.
2. Description of the Prior Art
Optical fiber connectors are used to optically couple one optical fiber to either another optical fiber or an optical device, such as an LED, laser, or detector. One typical optical fiber connector for making an optical connection is referred to as a bayonet connector. The typical bayonet connector includes a connector housing having a barrel slidably mounted therein. The barrel has a ceramic, metal or plastic ferrule or plug, coupled to one end thereof. Each ferrule has a passageway extending longitudinally therethrough for receiving an end portion of the optical fiber. The barrel and ferrule are biased outwardly of the connector housing by a compression spring disposed about the barrel body. Connectors of this type are advantageous in that the ferrule plugs may be machined and polished to very close tolerances so that, when an end face of one ferrule engages an end face of another ferrule in a sleeve, for example, their respective passageways and optical fibers become coaxially aligned. The end faces of the ferrule plugs can be flat, or they can have a special shape (such as convex, slant or half-slant) which facilitates minimizing both power loss and reflection of light back into the transmitting fiber. Polishing the flat or special shapes requires special skills and equipment. In addition, the polishing of the flat or special shapes has to be performed with minimal roughness. If the passageways in the ferrules are not aligned, or the end faces of the ferrules are not flush, then the optical signal transmitted between the optical fibers becomes disturbed or lost.
A problem with the use of the bayonet connectors of this type relates to the potential for optical disconnection when the end face of the ferrule becomes disengaged from the end face of the ferrule in the optical connector or optical device. It will be recalled that the barrel and ferrule are biased outwardly by the compression spring. A typical optical fiber cable has strain relief strands associated therewith. In a typical bayonet connector, the strain relief strands are secured to the barrel. If sufficient force is applied to the optical fiber cable (for example, in the direction away from the optical connection), then the end faces of the ferrules will be pulled apart. This will cause the optical fibers to become disconnected and the optical connection terminated.
Another problem presented by bayonet connectors of the past is that they were not usually provided with premounted optical fibers. The user of the connectors had to mount the optical fiber from the optical fiber cable in the connector. The connectors had a passageway from the back of the connector to the front end of the ferrule. The customer had to put adhesive into this passageway and then insert the fiber from the optical fiber cable all the way through the connector until the optical fiber protruded out the front end of the ferrule. The user would conventionally cure the adhesive and then cleave the protruding portion of the fiber. The user would then grind and polish the optical fiber. All of these activities were time consuming and oftentimes required special skills and tools. It was not uncommon that the adhesive would be applied and cured improperly or the end face was polished or ground improperly, thereby making the connector unusable.
One optical fiber connector of the prior art is shown in U.S. Pat. No. 4,812,009, issued to Carlisle et al., on Mar. 14, 1989. This optical connector has a cap located near the end of an optical fiber cable. The cap has an extender which has one end threadably secured to the cap and a second end secured to the optical fiber cable. Thus, when bending forces applied to the cable were transferred at the location to the extender and then to the cap, the bending forces became transmitted through the extender to the cap. The problem with this design is its multi-piece construction which requires a cap and an extender which must be threadably secured to the cap. It is not uncommon that when these two pieces are threaded together, the optical fiber may become damaged.